on the plaintext. Algorithm itself is referred to as the Data Encryption Algorithm (DEA) Data are encrypted in 64-bit blocks using a 56-bit key. • Plaintext: This is the readable message or data that is fed into the algorithm as. • Encryption algorithm: The encryption algorithm performs various transformations. A public-key encryption scheme has six ingredients (Figure 9.1a; compare. 10 [2] William Stallings, “Cryptography And network Security: Principles and Practice second edition”, ISBN 0-13869017-0, 1995 by Prentice- Hall, Inc. Simon & Schuster / A with Figure 3.1). input. Keywords: Round, Output Transformation, Sub-Key, Symmetric Key Algorithm. The algorithm transforms 64-bit input in … by William Stallings Lecture slides prepared for “Cryptography and Network Security”, 6/e, by William Stallings, Chapter 3 – “Block Ciphers and the Data Encryption Standard”. Sixth Edition. Was the most widely used encryption scheme until the introduction of the Advanced Encryption Standard (AES) in 2001. Cryptography and Network Security. International Data Encryption Algorithm (Idea) For,….S.Artheeswari,etal,. INTRODUCTION: International Data Encryption algorithm (IDEA) is a block cipher algorithm designed by Xuejia Lai and James L. Massey of ETH-Zürich and was first described in 1991.The original algorithm went through few modifications and finally named as International Data Encryption Algorithm (IDEA).